In general, connectors are welded to a circuit board for receiving proper electronic elements so as to achieve a preferred connection between the electronic elements and the circuit board. For a pin grid array (PGA) chip, it is desired to have a zero inserting force (ZIF) as a terminal is inserted into the connector.
For the terminals of the connectors of a ZIF chip connector, the chip connector can be classified as two classes. In one kind, the terminal has a single one contacting arm, and a pin extending from a lower side of the chip serves to clamp the contact arm so as to achieve electric and mechanic connections between the connector and the pin of the chip. These kinds of terminals are disclosed in for example U.S. Pat. Nos. 3,315,212, 4,501,461, 4,674,811, 4,887,974, 4,988,310, 5,013,256, and 5,052,101, etc.
Another kind of terminal has two contact arms, in that a pin extends from the lower end of the chip serves to be clamped between two contact arms so as to achieve electric and mechanic connections between the connector and the pin of the chip. These kinds of terminals are disclosed in for example U.S. Pat. Nos. 3,676,872, 3,763,459, 4,331,371, 4,381,130, 4,397,512, 4,468,072, 4,498,725, 4,648,669, etc. Terminals with two contact arms have a preferred elasticity so that as the pin of a chip is inserted into the connector, a preferred electric and mechanic connection is achieved.
Referring to FIG. 1, a prior art terminal is shown, in that the terminal 10a has a Y shape and a bending portion 11a is installed at the middle portion thereof. A lower end of the bending portion 11a is formed with a thin long inserting portion 12a. The upper end of the inserting portion 12a is extended with two forked arms. The upper end of one arm is a contact portion 13a. The inner side of the contact portion 13a is extended with a tilt guiding portion 14a. Two sides of the upper end of the terminal 10a are formed with positioning teeth 15a for being buckled to the inner wall of the connector.
However, in the prior art terminal structure, the arms of the contact portion 13a are extended from the middle portion of the terminal 10a. The lower end of the arm has a wider portion serving to be connected to the upper end of the terminal 10a. Therefore, the elasticity of the contact portion 13a is low and the tightness of the terminal and the pin of a chip is not good so that it is hard to achieve a required electric and mechanic connection.